From 3f26080658cdb447fc6d06ea8f7a34221db78f6c Mon Sep 17 00:00:00 2001 From: Matthias Maier Date: Fri, 15 Jun 2018 14:38:42 -0500 Subject: [PATCH] step-1: Reflow two paragraphs --- examples/step-1/step-1.cc | 78 +++++++++++++++++++-------------------- 1 file changed, 38 insertions(+), 40 deletions(-) diff --git a/examples/step-1/step-1.cc b/examples/step-1/step-1.cc index 512a2d2bfd..dbf94ccb07 100644 --- a/examples/step-1/step-1.cc +++ b/examples/step-1/step-1.cc @@ -95,50 +95,48 @@ void second_grid() const double inner_radius = 0.5, outer_radius = 1.0; GridGenerator::hyper_shell( triangulation, center, inner_radius, outer_radius, 10); - // By default, the triangulation assumes that all boundaries are - // straight lines, and all cells are bi-linear quads or tri-linear - // hexes, and that they are defined by the cells of the coarse grid - // (which we just created). Unless we do something special, when new - // points need to be introduced the domain is assumed to be - // delineated by the straight lines of the coarse mesh, and new - // points will simply be in the middle of the surrounding ones. - // Here, however, we know that the domain is curved, and we would - // like to have the Triangulation place new points according to the - // underlying geometry. Fortunately, some good soul implemented an - // object which describes a spherical domain, of which the ring is a - // section; it only needs the center of the ring and automatically - // figures out how to instruct the Triangulation where to place the - // new points. The way this works in deal.II is that you tag parts - // of the triangulation you want to be curved with a number that is + // By default, the triangulation assumes that all boundaries are straight + // lines, and all cells are bi-linear quads or tri-linear hexes, and that + // they are defined by the cells of the coarse grid (which we just + // created). Unless we do something special, when new points need to be + // introduced the domain is assumed to be delineated by the straight + // lines of the coarse mesh, and new points will simply be in the middle + // of the surrounding ones. Here, however, we know that the domain is + // curved, and we would like to have the Triangulation place new points + // according to the underlying geometry. Fortunately, some good soul + // implemented an object which describes a spherical domain, of which the + // ring is a section; it only needs the center of the ring and + // automatically figures out how to instruct the Triangulation where to + // place the new points. The way this works in deal.II is that you tag + // parts of the triangulation you want to be curved with a number that is // usually referred to as "manifold indicator" and then tell the - // triangulation to use a particular "manifold object" for all - // places with this manifold indicator. How exactly this works is - // not important at this point (you can read up on it in step-53 and - // @ref manifold). The functions in GridGenerator handle this for us in most - // circumstances: they attach the correct manifold to a domain so that when - // the triangulation is refined new cells are placed in the correct + // triangulation to use a particular "manifold object" for all places + // with this manifold indicator. How exactly this works is not important + // at this point (you can read up on it in step-53 and @ref manifold). + // The functions in GridGenerator handle this for us in most + // circumstances: they attach the correct manifold to a domain so that + // when the triangulation is refined new cells are placed in the correct // places. In the present case GridGenerator::hyper_shell attaches a // SphericalManifold to all cells: this causes cells to be refined with - // calculations in spherical coordinates (so new cells have edges that are - // either radial or lie along concentric circles around the origin). + // calculations in spherical coordinates (so new cells have edges that + // are either radial or lie along concentric circles around the origin). // - // By default (i.e., for a Triangulation created by hand or without a call - // to a GridGenerator function like GridGenerator::hyper_shell or - // GridGenerator::hyper_ball), all cells and - // faces of the Triangulation have their manifold_id set to - // numbers::invalid_manifold_id, which is the default if you want a - // manifold that produces straight edges, but you can change this - // number for individual cells and faces. In that case, the curved - // manifold thus associated with number zero will not apply to those - // parts with a non-zero manifold indicator, but other manifold - // description objects can be associated with those non-zero - // indicators. If no manifold description is associated with a - // particular manifold indicator, a manifold that produces straight - // edges is implied. (Manifold indicators are a slightly complicated - // topic; if you're confused about what exactly is happening here, - // you may want to look at the @ref GlossManifoldIndicator "glossary - // entry on this topic".) Since the default chosen by - // GridGenerator::hyper_shell is reasonable we leave things alone. + // By default (i.e., for a Triangulation created by hand or without a + // call to a GridGenerator function like GridGenerator::hyper_shell or + // GridGenerator::hyper_ball), all cells and faces of the Triangulation + // have their manifold_id set to numbers::invalid_manifold_id, which is + // the default if you want a manifold that produces straight edges, but + // you can change this number for individual cells and faces. In that + // case, the curved manifold thus associated with number zero will not + // apply to those parts with a non-zero manifold indicator, but other + // manifold description objects can be associated with those non-zero + // indicators. If no manifold description is associated with a particular + // manifold indicator, a manifold that produces straight edges is + // implied. (Manifold indicators are a slightly complicated topic; if + // you're confused about what exactly is happening here, you may want to + // look at the @ref GlossManifoldIndicator "glossary entry on this + // topic".) Since the default chosen by GridGenerator::hyper_shell is + // reasonable we leave things alone. // // In order to demonstrate how to write a loop over all cells, we will // refine the grid in five steps towards the inner circle of the domain: -- 2.39.5